With rapid development of the mobile Internet, users have increasingly high demands for mobile high-speed data access. As a low-cost and high-bandwidth wireless access technology, a wireless local area network (WLAN) has been deployed in a large scale and applied widely by domestic and overseas operators.
In a process of using the WLAN, a situation in which multiple terminals (Stations (STAs)) access a same access point (AP) often occurs, and a situation in which multiple STAs simultaneously need to send data to a same AP also often occurs. The multiple STAs cannot send uplink data simultaneously due to a restriction on an available frequency band allocated to the STAs and the AP. In this case, a backoff mechanism may be employed among the multiple STAs to determine which STA sends data at a moment.
The backoff mechanism refers to that all STAs accessing a same AP share a time domain and a frequency domain, and in the time domain, only one STA can send data at a same moment, while all other STAs wait for sending data, that is, all the other STAs perform backoff. After a current STA completes data sending and after an interval of one distributed interframe space (DIFS), all the STAs contend in a contention window (CW), and a STA with a strongest contention capability obtains, by means of contention, an opportunity for sending data, while other STAs continue to wait for sending data.
There are many factors that determine a contention capability of a STA, such as signal quality, a processing speed, signal strength, and a demand, among which a primary factor that determines the contention capability of the STA is the demand, that is, the STA has a demand for sending data. Generally, in a case in which other factors are the same, a stronger demand of the STA indicates a higher probability that the STA obtains, by means of contention, an opportunity for sending data. For an AP, if an actual data sending rate of a STA is greater, it may be considered that the STA has a higher demand.
In a case in which other factors are the same, if some STAs have stronger demands, probabilities that these STAs obtain, by means of contention, opportunities for sending data are higher. Conversely, if some STAs have weaker demands, probabilities that these STAs obtain, by means of contention, opportunities for sending data are lower. A delay of sending data by a STA with a relatively low demand is relatively large due to waiting for multiple times, and in an extreme situation, sending may fail because of always failing to obtain, by means of contention, an opportunity for sending data, which causes quite poor experience to a user of a terminal.
It can be seen that, in the prior art, contention among terminals is mostly adjusted according to a contention window, and demands of the terminals are not adjusted, thereby causing that a terminal with a higher demand excessively preempts a terminal with a lower demand, and leading to poor experience when the terminals are used.